Method and apparatus for crimping electrical connectors



March 26, 1968 J. w. BALDYGA 3,374,657

METHOD AND APPARATUS FOR CRIMPING ELECTRICAL CONNECTORS Filed May 24,1965 3 Sheets-Sheet l INVENTOR. JO PH W. BALDYGA ATTORNEYS March 26,1968 J. w. BALDYGA 3,374,657

METHOD AND APPARATUS FOR CRIMPING ELECTRICAL CONNECTORS Filed May 24,1965 3 Sheets-Sheet 2 FIG.3 I FIG.4

I INVENTOR. J EPH w. BALDYGA ATTORNEYS March 26, 1968 J. w. BALDYGA3,374,657

METHOD AND APPARATUS FOR CRIMPING ELECTRICAL CONNECTORS Filed May 24,1965 5 Sheets-Sheet Z FIGS as i. \i 34 I NVENTOR.

JO EP w. BALDYGA BY 4/ ATTORNEYS United States Patent Ofiice 3,374,657Patented Mar. 26, 1968 3,374,657 METHOD AND APPARATUS FOR CRIMPINGELECTRICAL CONNECTORS Joseph W. Baldyga, Utica, Mich., assignor toDiamond Die & Mold C0., Mount Clemens, Mich, a corporation of MichiganFiled May 24, 1965, Ser. No. 458,141 7 Claims. (Cl. 72413) ABSTRACT OFTHE DISCLOSURE Crimping apparatus and its method of operation comprisinga movable ram, a pair of toggle devices connected in series, crankmechanism connected to one of said toggle devices, said crank mechanismincluding a connecting rod, and drive means for effecting substantially360 rotation of the crank from a starting position in which theconnecting rod is in substantial alignment with a line joining the axisof the crank and the pivot connection between the links of the toggle towhich the crank is connected.

At the present time electrical connectors are crimped to the end ofinsulated wire by an operation in which one or more pairs of tabs formedon the electrical connector are crimped over into engagement with theelectrical conductor or the insulation surrounding the electricalconductor, or preferably both. The electrical connectors are ordinarilyformed of brass and it has been found that best results are obtainedwhen the crimping force is applied in such a way that substantially themaximum crimping force is maintained for a sensible time interval. Inother words, crimping by impact is not satisfactory.

It is an object of the present invention to provide a method andapparatus for crimping electrical connectors to insulated conductorscharacterized in the provision of maintaining crimping pressure for asensible interval as for example about one-tenth of a second.

More specifically, it is an object of the present invention to provide amethod and apparatus for crimping electrical connectors to conductorsemploying double toggle mechanism with the result that movement of thecrimping ram or press into final position is relatively slow and resultsin maintaining substantially maximum crimping pressure for a sensibleinterval.

It is a further object of the present invention to provide crimpingmechanism of the character described comprising a rotatable driver,toggle actuating mechanism, selectively operable means for connectingthe toggle actuating mechanism to the driver, and means forautomatically disengaging the toggle actuating mechanism from therotating driver after one actuation of the toggle mechanism.

It is a further object of the present invention to provide apparatus ofthe character described comprising a crimping ram, a toggle connected tosaid crimping ram, a second toggle connected to the first mentionedtoggle, and means for actuating the second toggle to produce movement ofthe crimping ram characterized in extremely slow movement of the finalcrimping position, and extremely slow movement out of crimping positionso that in effect, substantially maximum crimping pressure is maintainedfor a sensible interval.

It is a further object of the present invention to provide crimpingmechanism comprising a rotary member adapted to move throughapproximately 360 degrees to effect a single crimping operation, acrimping ram, toggle mechanism connected between said ram and saidrotary member, a cam connected to said rotary member, and work feedmechanism actuated by said cam.

It is a further object of the present invention to provide apparatus asdescribed in the preceding paragraph in which the cam for actuating thework feed mechanism is provided with an abrupt fall-off positioned toregister with a cam follower when the toggle mechanism is insubstantially collapsed position.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, illustrating a preferred embodiment of theinvention, wherein:

FIGURE 1 is an elevational view of the crimping apparatus.

FIGURE 2 is a plan view of the apparatus shown in FIGURE 1, partlysectioned on line 22, FIGURE 1.

FIGURE 3 is an elevational View of the apparatus shown in FIGURE I,viewed from the right.

FIGURE 4 is a sectional view on the line 44, FIG- URE 1.

FIGURE 5 is a sectional view on the line 55, FIG- URE 1.

FIGURE 6 is a fragmentary sectional view on the line 66, FIGURE 4.

FIGURE 7 is a fragmentary perspective view showing an electricalconnector crimped to an insulated electrical conductor.

Referring first to FIGURE 7 there is illustrated a typical applicationof the crimping operation to connect an electrical connector to aninsulated electrical conductor. As seen in this figure, the insulatedelectrical conductor comprises an elongated electrical conductingelement such for example as a copper wire or assembly of copperfilaments indicated at 10. Insulation 12 surrounds the electricalconductor. The electrical connector, which may be of brass or the like,may be in the form of a plate 14 having a pair of ears or tabs 16adapted to be bent around and crimped into clinched engagement with theinsulated conductor, and more specifically, with the insulating cover 12thereof. At the same time, a pair of smaller ears or tabs 18 areprovided which are crimped around and firmly clinched to the bared endof the electrical conductor. The plate 14 may be provided with suitableformations for cooperation with elements of an electrical circuit and inthe present instance this is illustrated simply as comprising a circularopening 20 formed in the end portion of the connector.

Since the electrical connector has two pairs of tabs which arerespectively firmly clinched to the insulating cover of the electricalconductor and to the conducting core or element thereof, the connectoris firmly and permanently attached to the conductor.

It has been found that the clinching of the tabs to the conductor asabove described is best accomplished when crimping pressure is appliedin such a way that substantially maximum pressure is maintained for asensible interval. This is to be contrasted with a clinching operationin which tabs are clinched by extremely brief application of pressuresuch for example as by impact.

The method suggested in the foregoing is adapted to be carried out bythe apparatus illustrated herein.

Referring now to FIGURES l-6, the apparatus comprises a frame 22 towhich a motor 24 is connected, the motor driving a pinion 26 which is inmesh with a gear 28 mounted for free rotation on a shaft 30. Securelyfixed to the shaft 30 is a collar 32 the connection to the shaft beingillustrated in FIGURE 4 as including a pointed set screw 34, the pointedend of which is received in a recess in the shaft 30. Slidably carriedby the collar 32 in a channel 36 is a pin 38 having a radiallyprojecting dog 40. The pin 38 is provided with an elongated recess 42 inwhich is received a compression spring 44 the outer end of which seatsagainst a disc 46. With this arrangement the spring 44 biases the pin 38to the right as seen in FIGURE 4. Movement of the pin 38 to the right.is

3 normally prevented by engagement between the dog 40 on the pin 38 witha depending flange 48 formed on a lever 50 which is pivoted as indicatedat 52 and is adapted to be moved upwardly by momentary energization ofthe windings of a solenoid 54. The gear 28 is provided with a plurality,as for example six, openings in circumferential alignment with the pin38 and when the pin is freed for movement under the action of the spring44 the pin moves into the next opening in the gear, and thus, direct- 1ymechanically couples the gear 28 to the collar 32. As a single rotationof the collar 32 nears completion, the dog 40 on the pin 38 engages acamming surface on the flange 48 so that the pin is retracted from theopening in the gear 28. The lever 50 carries a dog 56 which is engagedby the dog 40 on the pin, thus arresting rotation of the collar 32 after360 degreess rotation.

The collar 32 of course, during its rotation imparts rotation to theshaft 30 and this shaft in turn rotates a combined cam and crank arm 58having a crank pin 60 there Mounted on the exterior of the frame 22 is apivot mounting pin 62, the pin being rigidly mounted in a boss 64 asbest seen in FIGURE 2. Connected to the pin 62 are a pair of links 66which are connected by a pivot pin 68 to a pair of links 70 and a secondpair of links 72. The links 72 have the opposite end connected to crankpin 60. Links 70 are connected to a pin 74 and to this pin are alsoconnected the links 76 and 78. The opposite end of the links 76 areconnected to a pin 80 which in turn is supported in openings in aplurality of leaves 82 formed on a support member 84 having the circularflange 86 engaged against a threaded abutment member 88. Support 84 isretained in assembled relation against the adjustable abutment member 88by a screw 90 carried by a cap 92.

The other ends of the links 78 are connected to a pin 94, the pin beingcarried by a driver 96, the driver having a circular base portion 98 andvertically extending leaves 100, and a central relatively thick leaf102. The circular base of the driver 98 is received in a similarlyshaped recess 104 in the ram 106 which is vertically slidable in a guidehousing 108, as best seen in FIGURE 2. In this figure it will beobserved that the ram 106 has four corner portions 110 each of which isguidingly received in a correspondingly shaped corner 112 of the guideand housing member 108. Thus, the ram 106 is firmly supported forrectilinear movement upon actuation of the toggle mechanism. It will befurther -be apparent that the downward limiting position of the ram 106may be accurately predetermined by adjustment of the adjustable abutmentmember 88.

Referring now to FIGURE 1 it will be observed that the links 66 and 70form a first toggle in which the toggle elements are moved intosubstantial alignment when the actuating links 72 are in the positionshown in this figure. The first toggle mechanism comprising the links 66and 70 is connected to the second toggle mechanism comprising the links76 and 78 and the relationship is such that when the links of the firsttoggle mechanism approach substantial alignment the links 76 and 78 ofthe second toggle mechanism also approach alignment. Thus, it isapparent that as the ram 106 approaches its lowermost position, it ismoving extremely slowly and also it is capable of applying forces ofrelatively great magnitude with only moderate power being supplied tothe drive pinion 26.

More important than the relatively great magnitude of the pressurecapable of being applied by the ram is the fact that the describedarrangement in efiect operates to maintain the pressure applied to awork piece such as an electrical connector, at approximately the samepeak value for a sensible interval. In practice, the apparatus issemiautomatic in that the uncrimped connectors are automatically fed tocrimping position while the ram is at the top of its stroke and theoperator inserts the prepared conductor end so that the bared conductoris positioned between one pair of tabs, and the insulating coveradjacent the bared ends is positioned between the other pair of tabs onthe connector. At this time the operator energizes the solenoid 54momentarily. In practice, the solenoid may be energized by dischargefrom a condenser. Energization of the solenoid raises the lever 50 andreleases the pin 38 for movement into coupling engagement with the gear28. The collar 32 is given 360 degrees rotation and as it completes suchrotation the pin is retracted so as to disconnect the collar from thegear and rotation of the collar and associated mechanism is terminatedin precise position by engagement between dogs 40 and 56.

Referring to FIGURE 1, there is illustrated a cam surface engageable bya roller 122 on a lever 124 pivoted to the frame 22 as indicated at 126.The lever 124 is biased to the left as seen in this figure by a tensionspring 128 and is adapted to connect with mechanism (not shown) foreffecting feed of an uncrimped connector into position beneath the ram106. Details of the crimping head and the base which receives theuncrimped connector are omitted since these elements are of coursedesigned in accordance with each particular crimping operation to beperformed. It will be observed however, that the cam surface 120includes the abrupt fall-off portion 130 which is adapted to move intoposition adjacent the roller 122 when the two toggles are substantiallycompletely collapsed. Thus, feed of the connector is accomplished veryquickly when the ram is in its uppermost position, thus affordingmaximum clearance and at the same time, the arrangement provides for aminimum of delay in conditioning the apparatus for the succeedingcrimping operation.

While the force supplied in the crimping operation is of course variablein accordance with the particular connector, it has been observed that apressure of 23,400 pounds has been developed when the press is .001"displaced from its maximum downward movement, using a /z horsepowermotor operating at 1750 r.p.m. The gear ratio between the pinion 26 andthe gear 28 is such that shaft rotation is at the rate of r.p.m. This ofcourse means that only .333 second are required for complete rotation ofthe shaft or for a complete downward and upward reciprocation of theram. However, with the arrangement of the crank and double toggle, abouthalf of this time or approximately one-sixth of a second, is taken up bythe last .015" of movement of the ram. Thus, the cycle involves acrimping operation in which the pressure is increased at a controlledbut increasing rate and is maintained at relatively high values for asensible interval. While variations are possible and are in accordancewith the material and shape of the connectors, it may be stated that theapplication of pressure adequate to crimp the connector tabs intorequired position should be maintained for an interval of at least .100second.

The drawings and the foregoing specification constitute a description ofthe improved method and apparatus for crimping electrical connectors insuch full, clear, concise and exact terms as to enable any personskilled in the art to practice the invention, the scope of which isindicated by the appended claims.

What I claim as my invention is:

1. A crimping press comprising a base, a ram slidable on said base, afirst toggle connected between said base and ram and having a firstmovable pivot and links connected thereto and movable into substantialalignment to exert maximum crimping force, a second toggleconnectedbetween said base and the movable pivot of said first toggle, saidsecond toggle comprising a first link pivoted to said base, a secondlink pivoted to the movable pivot of said first toggle, and a secondmovable interconnecting the links of said second toggle, and actuatingmeans comprising a crank carried by said base, a connecting rodconnecting said crank to said second pivot, and means for driving saidcrank through substantially 360 from a starting position in whichsaidconnecting rod extends in substantial alignment with a line joining theaxis of said crank and said second pivot.

2. In a press of the character described a base, a vertical column onsaid base, a hollow ram slidable longitudinally in said column, a firsttoggle seat mounted in said column for adjustment longitudinallythereof, a second toggle seat in said ram, a first toggle connectedbetween said first and second toggle seats, said column having a lateralopening, a second toggle extending through said opening having one endconnected to said first toggle and the other end connected to said base,a crank on said base, and a connecting rod connecting said crank to saidsecond toggle, said column being of generally rectangular internalcross-section providing four guide corners, said ram being elongated andof corresponding rectangular cross-section and having four cornersslidably received in the guide corners of said column, said ram havingopenings at its top and at one side, said first toggle being received insaid ram and extending through the top opening thereof, said secondtoggle extending through the side opening thereof.

3. Apparatus as defined in claim 2 in which said toggle seats comprisemembers having a plurality of fiat apertured parallel leaves, saidtoggle comprising a plurality of flat parallel links pivotally connectedat one end to said leaves and at the other end to each other.

4. In a press of the character described, a base, a vertical column onsaid base, a hollow ram slidable longitudinally in said column, a firsttoggle connected between said column and said ram, a second toggleconnected between said first toggle and said base, both of said togglescomprising a pair of links each of which is made up of a plurality offlat parallel elements, the elements of each link being interleavedbetween the elements of another link pivotally connected thereto.

5. In a press of the character described, a base, a vertical column onsaid base, a hollow ram slidable longitudinally in said column, a firsttoggle connected between said column and said ram, a second toggleconnected between said first toggle and said base, a crank on said base,a link connecting said crank to said second toggle, a crank shaft towhich said crank is secured, a collar fixed to said shaft, a gearrotatable on said shaft, a pin slidable on said collar parallel to saidshaft and in position to engage a side of said gear, a pin receivingopening in the side of said gear, a spring urging said pin toward saidgear, a lever, a dog on said pin engaging said lever and retainedthereby against movement into an opening in said gear, means forswinging said lever to release said dog, camming means on said leverengageable by said dog to cam said pin out of the opening in said gearas said collar completes one revolution, and a dog on said leverengageable by the 'dog on said pin to arrest rotation of said collar andshaft after 360 degrees rotation.

6. In a press of the character described, a base, a vertical column onsaid base, a hollow ram slidable longitudinally in said column, a firsttoggle connected between said column and said ram, a second toggleconnected between said first toggle and said base, a crank on said base,a link connecting said crank to said second toggle, a crank shaft towhich said crank is secured, means for driving said shaft through onerotation, stop means for limiting rotation thereof, a cam on said crank,feed actuating means comprising a cam follower, said cam having anabrupt fall-off cam surface in position to be engaged by said followerwhen said toggles are collapsed, and resilient means connected to saidfollower to provide for abrupt actuation of feed means when said ram isfully retracted.

7. In a press of the character described, a base, a vertical column onsaid base, a hollow ram slidable longitudinally in said column, a firsttoggle seat mounted in said column for adjustment longitudinallythereof, a second toggle seat in said ram, a first toggle connectedbetween said first and second toggle seats comprising linksinterconnected by a first pivot, said column having a lateral opening, asecond toggle extending through said opening comprising a first linkhaving one end connected to the pivot of said first toggle and a secondlink having one end connected to said base, a second pivot connectingthe links of said second toggle, a crank on said base, and a connectingrod connecting said crank to said second pivot, and drive means for saidcrank including means to limit rotation thereof upon initiation of acycle to substantially 360 from a starting position in which saidconnecting rod extends in substantial alignment with a line joining theaxis of said crank and sad second pivot.

References Cited UNITED STATES PATENTS 1/1854 Lester 72-451 5/1931 Rees72-451

